Author Topic: Real Bull mini-lathe circuit board diagrams.  (Read 8308 times)

Offline andyf

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    • The Warco WM180 Lathe - Modifications
Real Bull mini-lathe circuit board diagrams.
« on: March 30, 2012, 03:21:43 PM »
I was contacted recently by a gentleman called Pat Darragh, who had seen a bit of info on my website about the KB Electronics KBIC/KBLC 240 control boards - the type I use to run the treadmill motor on my old milling machine. He has a Chester Conquest, which like the mini-lathes supplied in the UK by Warco and Amadeal, comes from the Real Bull stable cattle shed in China.

It turns out that he is conversant with electronics. He must be patient, too,  because he has analysed and drawn up both the speed control board and the ancilliary board which turns the motor on and off, brakes it, and provides the 5v power supply for the tachometer sensor and display.

He has very kindly allowed me to put his work on my website so it reaches a wider audience. If anyone needs it, it starts half-way down this page: 
< http://andysmachines.weebly.com/variable-speed-controls.html >.

Andy
Sale, Cheshire
I've cut the end off it twice, but it's still too short

Offline Stilldrillin

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Re: Real Bull mini-lathe circuit board diagrams.
« Reply #1 on: March 30, 2012, 05:56:23 PM »
Thanks Andy, and Pat!  :thumbup:

I'll probably need some of that info, eventually........  :palm:

David D
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

Offline hopefuldave

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Re: Real Bull mini-lathe circuit board diagrams.
« Reply #2 on: April 05, 2012, 08:03:12 PM »
More thanks to you both! I have a number of "fried" KB boards, if I can repair 'em they can be pressed into service...

I'm attempting a task like Pat's on the thyristor controllers found in some of the small milling machine power feeds - if I can get it worked out I'll post the diagram; Andy, you'd be welcome to put it on your site?

Dave H. (the other one)
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Offline andyf

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Re: Real Bull mini-lathe circuit board diagrams.
« Reply #3 on: April 06, 2012, 11:53:52 AM »
More thanks to you both! I have a number of "fried" KB boards, if I can repair 'em they can be pressed into service...
I'm attempting a task like Pat's on the thyristor controllers found in some of the small milling machine power feeds - if I can get it worked out I'll post the diagram; Andy, you'd be welcome to put it on your site?
Dave H. (the other one)

Hi Dave,

As to your fried KB boards, and in case it helps, I was contacted by a Dutch chap who had blown a power diode on the KBIC/KBLC 240 board in his minilathe, seeking help in finding replacement power diodes. His Gooling the "D8010L" on the parts list didn't produce results. I located some in the UK - an extract from my reply to him appears below in blue, to save my typing finger.

If you are making a power feed for a small mill, you might consider a 12V motor powered by something like the Velleman K8004 PWM power control; get to it from this page:
< http://www.esr.co.uk/velleman/products/index_kit.htm >.
Geared 12V motors from China which do 30, 60 or 120 RPM are under 10 on Ebay, and one of them will happily push along the table of my small Dore Westbury miller.

Andy.

The D8010L is a 10A diode, and the D8020L is 20A. You could use two D8020L diodes; one of them would be overspecified, but that would not make any difference to its operation.
 
This seems to be a suitable source < http://parts.digikey.co.uk/1/1/264192-rectifier-800v-20a-220-d8020l.html > . They charge a lot for shipping, though the diodes are not expensive at about 2 Euros each.
 
Here is another UK supplier < http://www.dalbani.co.uk/catalogue/product_details.php?id=34855 >. I don't know how much they charge for shipping, because you have to register on the site before ordering.
 
I found them by Googling "Teccor D8020L".
Sale, Cheshire
I've cut the end off it twice, but it's still too short

Offline Bluechip

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Offline hopefuldave

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Re: Real Bull mini-lathe circuit board diagrams.
« Reply #5 on: April 06, 2012, 03:25:40 PM »
Thanks very much, gents!

The SCR and diode spec's make sense, partiularly the "isolated tab" parts - can't bear to think of what'd happen with the heatsink/bracket shorting the two SCR's....

The mill power feed's a ready-built unit sold for one of the Chinese small mills (OK, it's actually three of 'em rescued from a skip...) - it has a 90V DC motor in it, and a tendency for the control board to burst into flames... Fortunately I have a known-good board to work from! I have to admit I'm a bit worried by the 90V motor being fed from the 240V mains, strikes me that could be why the controllers aren't too reliable...

Dave H. (the other one)
Rules are for the obedience of fools, and the guidance of wise men.